Classifications

• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
  • C03C3/00—Glass compositions
  • C03C3/04—Glass compositions containing silica
  • C03C3/076—Glass compositions containing silica with 40% to 90% silica, by weight
  • C03C3/089—Glass compositions containing silica with 40% to 90% silica, by weight containing boron
  • C03C3/091—Glass compositions containing silica with 40% to 90% silica, by weight containing boron containing aluminium
  • C03C3/093—Glass compositions containing silica with 40% to 90% silica, by weight containing boron containing aluminium containing zinc or zirconium

Definitions

• the thermal coe'fficient of expansion of the sintered glass layer must substantially match the coefiicient of expansion of the ceramic substrate so that following the sintering the glass will not crack, craze, or cause significant warpaging of the module.
• Another requirement is that thedielectric constant of the glass be relatively low in order that the capacitance between'the metallurgy layers remains low.lf. the capacitance is increased substantially, the speed of the device module combination would be reduced limiting its usefulness, particularly in high-performance computer applications. Glass compositions known to the prior art do not meet all of .the
• amounts over32 percent in the composition causes the resultant composition 'to loose chemical durability. Any amount under -25 percent increases the sintering temperature of the composition above the desired limit. In regard to CaO, more than 2 percent raises the sintering temperature while any amount less than 1 percent causes the composition to loose than 2 percent of K 0 results in a high softening point-while :greater than 4 percent causes a lowering of the sofiening 75.
• BaO inthe composition improves the linear expansion.
• this constituent in amounts greater than 3 percent will produce in the glass a high softening point or sintering temperature.
• MgO is needed for limiting phase separation. However, in amounts less than 0.25 percent the effect is not achieved. In amounts greater than 0.75 percent there is an objectionable increase in sintering temperature.
• ZrO is provided for basically the same reason as MgO. However, in amounts over 0.75 percent no further beneficial efi'ect results, but additional amounts will increase the softening point whichis objectionable. In general all of the constituents with the exception of 8,0; increase the dielectricconstant. However, the amount of B 3 cannot exceed 32 percent because it results in a loss of chemical durability.
• the above glass composition represents a delicate and critical balance of a plurality of commonly known glass constituents which will produce the desired physical properties necessary in fabricating a glass metal ceramic module.
• a preferred specific embodiment of the aforediscussed glass I composition contains 60 percent SiO 29 percent B 0 2 percent CaO, 1 percent A1 0 3 percent Na,(), 1 percent BaO, 0.5 percent ZrO 0.5 percent MgO.
• This composition has the following properties:
• the glass of the subject invention When the glass of the subject invention is formulated with a B 0 content in the high end of the range given above, a lowering of the dielectric constant will be realized. However, chemical durability and softening point will also be lowered. This can be compensated by including amounts of CaO+BaO in amounts in the higher end of the ranges set forth. This would, within limits, improve the dielectric constant and chemical durability of the glass while keeping the softening point on the order of 800 C. as required.
• the aforedescribed glass composition, as well as other glasses, that are capable of phase separation can be strengthened very significantly by suitable heat treatment. It has been established that when a glass, for example, a borosilicate glass is heat treated at temperatures above 490, or above the annealing point, there occurs a phase separation into two immiscible-glass phases. The mechanism of phase separation is spinodal below about 650 C., while at high temperatures, nucleation and growth type of phase separation occurs. The micro structure of the spinodal separation is ex tremely connective and therefore strong, while that of the nucleation and growth of phase separation displays sigiificantly less strength. The objective then of a heat treatment is to promote spinodal phase separation.
• the aforedescribed glass composition When the aforedescribed glass composition is sintered and cooled relatively rapidly following the sintering operation a nucleation and growth type of phase separation is formed within the layer. However, if the glass layer is reheated to a temperature on the order of 600 C. for a time on the order of 5 hours, the I spinodal phase separation occurs. Conversely, if the glass layer is heated to a temperature on the order of 750 C. for a time of the order of 5 hours the nucleation and growth type of phase separation occurs.
• the suggested heat treatment for strengthening a glass that is capable of phase separating is to heat the composition at the temperature for forming spinodal phase growth for a time sufficient to promote the growth.
• the proper temperature for a specific glass composition can be determined from a phase diagram of the composition.
• composition of claim 1 wherein the B 0 content is in the range of 25-27 percent by weight.
• composition of claim 1 wherein he B 0 content is in the range of 28-30 percent by weight.
• composition of claim 1 wherein the B 0 content is in the range of 30-32 percent by weight.

Landscapes

• Chemical & Material Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Geochemistry & Mineralogy (AREA)
• Materials Engineering (AREA)
• Organic Chemistry (AREA)
• Glass Compositions (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

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Family Applications (1)

Country Status (5)

Cited By (5)

Citations (3)

• 1970
  • 1970-11-20 US US91599A patent/US3640738A/en not_active Expired - Lifetime
• 1971
  • 1971-09-28 FR FR717135369A patent/FR2115149B1/fr not_active Expired
  • 1971-10-28 IT IT30452/71A patent/IT939134B/it active
  • 1971-11-04 CA CA126,922A patent/CA960852A/en not_active Expired
  • 1971-11-17 DE DE19712156969 patent/DE2156969A1/de active Pending

Patent Citations (3)

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